In the past, when composite parts had to be joined through a hinge connection so as to be pivotable about that hinge with respect to one another, it was common practice to use a conventional metal hinge of the piano hinge variety. The disadvantage of using such a metallic hinge rather than a composite hinge is increased weight, reduced strength, high manufacturing cost, possible interference with electrical system requirements, increased radar signature, the requirement that the metal hinge be made separately from the composite parts, and the requirement for drilling, fastening or bonding the metallic hinge to the composite parts which it joins. This drilling and fastener type connection between the metallic hinge and the composite part is unsatisfactory because of the low bearing strength of composites.
While injection molded thermoplastic hinges are presently available of the same design as the prior art metal piano-type hinges, these thermoplastic hinges are not compatible with the epoxy resin composites used throughout many industries today, are low in strength, have limited service capability, and are not capable of joining the two composite structures during the manufacturing process. These thermoplastic hinges must also be fabricated separately, and separately fastened to the composite members being joined in the same fashion that the metal hinges require such separate fastening.